Thyroid UK

Puzzled by blood test results - T3 -seeking advice

Hello Everyone,

I have just been moved to a new brand of levothyroxine ( 225 mg per day) - this has been an unpleasant experience ( raised pulse, night sweats and headaches) the doctor agreed to test after 3 weeks as I felt terrible. The results confirmed the dose was too high ( advice to reduce to 200 mg) . I took this opportunity to ask for my T3 levels to be tested for the first time.

I have been following the chats about feeling better if you can increase your T3 . I have taken levothyroxine for more than 20 years but continue to suffer with low thyroid symptoms such as hair loss, weight gain despite diet and exercise, memory and loss of brain function, brain fog, focus, concentration, irritability, anxiety, sleeping problems,and crippling fatigue /aching joints etc. So when the doctor sent me the following results I was surprised to see he thinks my T3 result is normal.

I have an appointment with a new and interested doctor this week to discuss my results but I don't know what to ask or do next ? It would be helpful if anyone can suggest how two results are out of the normal range but the T3 is normal ? Will they change once I reduce the amount of medication?

Test results - below

My T4 result 26.40 ( per paperwork they should be between 12.0 - 22.0 )

My THS result 0.100 (should be 0.27 - 4.2)

Had to chase three time for T3 result here is what the doctor wrote:

T3 is 5,00 pmol/l which is completely normal (normal values 3,16 – 8)

I would be grateful with any advice you can offer

Thanks Suz

4 Replies


THS: 0.100 (0.27 - 4.2)

FT4:26.40 (12.0 - 22.0 )

FT3: 5.00 pmol/l (3.16 – 8)

Is the range for FT3 correct? Should it be 3.1-6.8?

These results are very similar to what mine have been like for years although my FT4 was higher, up to 30 at one point. I have been taking Levo for over 40 years, I was still symptomatic, my then doctor was allowing me to have higher and higher doses, my FT4 was going higher and higher over range, but I wasn't getting any better. I took things into my own hands in the end.

Two things could be happening here.

1) You are not converting T4 to T3 well enough. Good conversion takes place when FT4:FT3 ratio is 4:1 or below. Yours is 5.28 : 1

2) You could be overmedicated - I didn't believe this because I was having hypo symptoms like you - but I bet if your reverse T3 was tested you'd find that instead of the T4 converting to T3, it's making some reverse T3 as well.

My reverse T3 was/is high. Reverse T3 can give hypo like symptoms.

Doctors don't generally have any knowledge of reverse T3, not that many seem to understand poor conversion either.

By the way, low or suppressed TSH has no relevance when taking Levo. [The only thing TSH is useful for is when it is high and used to diagnose hypothyroidism.] It just means that the pituitary gland recognises the fact that thyroxine is there (ie you're taking Levo) so it doesn't need to stimulate the thyroid to produce any (TSH = Thyroid Stimulating Hormone).

Also, it would be useful to have the following tested if not already done:

Vit D




All these need to be optimal (not just in range) for thyroid hormone to work properly. Ask for them to be tested and post results with reference ranges for comment.

1 like

Hello SeasideSusie,

Thanks for your advice .

I copied the T3 text from the doctors e-mail - I am living in The Netherlands so they might be using different lab numbers.

I am taking calcium and vitamin D12 - two large tablets a day as previous tests 6 years ago showed I had very low levels. I can ask about the tests - its a new doctor so I want to avoid missing a chance to find some relief from feeling grotty and tired day in, day out.

Your advice is gratefully recieved


I think the FT3 range will be 3.1-6.8, the others are the same as the private labs we use here and the FT3 is the one I quoted so I think the doctor's email may have a typo. 3.16-8 seems to be too wide a range.

What's vitamin D12? I'm only familiar with D3 but D2 can be given to vegetarian/vegan patients. Or is it B12?

How are your levels now? Do they keep an eye on them?


Hello Seaside Susie,

Thanks to your advice, I saw the new eager doctor !

He wants to test me in 6 weeks - I took the chance to ask for all the tests you suggested.

I am now cooling down( the night swets and racing heart are gone) - this is the second week on a reduced amount of Levo now 200 per day. The doctor said it was odd that I still felts sluggish and aching despite having too much Levo. I am just fed up of aching / creaking despite eating well and walking at least 10,000 steps a day.

A hospital trip 6 years ago resulted in the Calcium and D3 tablets - this will also be tested in early May.

Thanks for allowing me to rant, I often get to tell anyone anyone about feeling rotten - every day.


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